Y/N has just finished the hero course at her high school, but she is much too depressed to be doing anything. Her friends try to get her to do things again by making a bet with her. The bet involves repeating her last year, but at U.A. High, where Shouta Aizawa has just started working as a teacher. (Y/N is 19 in this, but pretends to be 18. Aizawa is 25.) Aizawa x student!Reader